The present invention relates to a miniature linear guide of the type that a slider incorporating ball circulating paths and supported on a guide rail is axially moved relative to the guide rail through a number of balls which circulate in ball rolling grooves while being rolled, and more particularly, to a dust-proof structure for the miniature linear guide.
A conventional miniature linear guide, as shown in FIG. 5, is made up of a long guide rail 1 substantially U-shaped in section, and a slider 2 which is slidably engaged with the guide rail 1. As shown in FIG. 6, the slider 2 integrally fits a slider body 3 substantially U-shaped in section which is formed of a plate material by pressing, a circulator 4 which is formed of plastic by molding and is mounted in a concave portion of the slider body 3, and a plastic holding plate 5 which is interposed between the slider body 3 and the circulator 4. Further, the circulator 4 includes ball circulating paths.
As shown in FIG. 6, load ball rolling grooves 1B are formed in the inner surfaces of two side walls of the guide rail 1, respectively, so that they are extended axially. Load ball rolling grooves 3B are formed in the outer surfaces of two side walls of the slider body 3, respectively, so that they are extended axially and confronted with the load ball rolling grooves 1B of the guide rail 1, respectively. A number of balls 6 are fitted in the spaces defined by the load ball rolling grooves 1B and 3B and in the ball circulating paths in the circulator 4. When the slider 2 is linearly moved along the guide rail 1, the balls 6 are infinitely circulated while being rolled.
The above-described conventional miniature linear guide has been proposed with the premise that it is used in a clean atmosphere as in a clean room which is substantially free from dust. Therefore, a dust-proofing device is not provided for the miniature linear guide. Hence, if it is used in a place where the atmosphere is not clean, dust may enter it, obstructing the operation.
In addition, the conventional miniature linear guide is disadvantageous in that, during operation, the lubricant such as grease and lubricating Oil splashes out through the gaps between the guide rail 1 and the slider 2, as a result of which the miniature linear guide is not sufficiently lubricated; that is, it is reduced in service life as much.